Switchboard signal-lamp.



E, B. CRA-FT. swITcHBOARD -SIGNAL LAMP.

v APPLICATION FILED FEB. 1l. 1007. 899,51 4:2

Patented sept. 29, 190s.

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I'ZDWA RD B. CRAFT, OIF WILMETZIIC, ILLINOIS,I ASSIGNOR TO WESTERN LEGTRIC COMPANY,

OF ClIlCAG/Lllliii-INOIS, A CORPORATION OF ILLINOIS.

SWITCHBOARD SIGNAL-LAMP.

Specification of Letters Patent.

Patented' sept. 29, 190s.

'indication filed February l, 197. Serial No. 355,184.

incandescent electric 15 linups, commonly used for signaling purposes on telephone switchboards, the buli is provided with two terminal plates secured upon opposite sides of said bulb. 'Ilie ordinary telephone-suitchboard has a series of lainp sockets each provided with contact springs between which a lamp is inserted, said springs engagingsaid terminal plates. Owing to the sinalliiess of such signal lamps, they are liable to injury, especially in the act of inserting them in their lfi'np sockets. ltis common, therefore, to i" avidel thc lamp with a base of some substantial non-combustible insulating material to which the. terminal 'plates are secured. lt has been .a-dillicult 3o mattei' to securely fasten said plates to the base and at the saine time to avoid all upstaiiding partswhich might interfere with the ready insertion of the lamp vinto its socket. By my invention, however, .l have 5 provided simple means for securing the plates to the base which provides a surface having no projecting parts. i

My invention may be morerezulily undcr Stood by reference to the accompanying Aie drawings, in which,

Figure l is a view showing the. lamp of my invention in position, the lam i socketbeing in section; Fig. 2 is a view in e evat-ion; Fig. 2% is a section on the line 3MB of Fig. 2; Fig. 4 isa rear end elevation; and Fig. 5 is a sec-tion on the line 5l-5 of Fig. 3.

Similar letters of reference designate like parts wherever they are shown.

ln the drawings, 1 designates the glass bulb of the lamp. 'lhe lainp lilainent iseon nected by lead-in wires in the usual way to the terminal )lates 2, V.Z,`which are secured u on the outside of the bulb. vEach of said p atcs is provided at its rear end with a tongue 8, preferably narrower than the plate, in order that shoulders or stops 4 may )e provided on eich side of said tongue b1 slitting the plate a short distance and ben y ing the slitted portions inwardly. l

The su porting base 5 "may be of any sult- 60 lable insu ating material, as for example, p0rcclain. Its lateral surface is provi( ed with longitudinally extended channels 6, 6, preferably rectangular in cross-section, as being of the simplest forni. each of a width and depth to receive its cor- 'i'esponding tongue, in order .that the outer surface may be flush and have no projecting parts.A

The bottom wall .of the channel 6 is prefer- 70 ably undercut at each end, as atv7 and 9 respectively. vThe undercut 9 may be formed by providing a conical-siu-kct in the end of the base which receives the inturned shoulders 4. bach into the undercuti? in the forni of a hook or lip t4. lt will be apparent, therefore, that since the lips N and -t extend towards each other, they tongue 3 is in effect dovetailed to the basel 5, as appears most 4clearly 80 in Fig. 3.

I have thus provided a simple and economical means for securely fastening the terminal plates to their supporting base and at the same time for providing no projecting 85 parts on the base.

I claim: l

lfln an incaiulescent electric lamp, the combination with a base-ofinsulating material, said base having channels in it-s lateral 90 surface, of a bulb and terminal plates secured to said bulb and base, said )lates being provided with tongues Ilying in c iannels ap proximately flush with the tops thereof and with intui'ned portions engaging said base at 95 eachv end of the channels to prevent the displacement of said tongues.

2.. ln'aii incandescent electricl lamp, the combination with a base ol' insulating material, said base having rectangular channels in its lateral surface, of abulband terminal plates secured to said bulb aiul base, said )lates being provided with narrowed tongues lying iii said channels. approximately flush. with the tops thereof, said plates also having inturned portions upon .each side of the tongues, and said tongues having. inturned lips at their rear ends, for engaging said base r at each end of the channels to securely hold said parts m their assembled position.

Said channels are 65 The end of the tongue 'l may be bent 75 f ion' ` 3. In ani incandescent electric lamp, the

combination with a base of insulating niaterial, said base having channels in its lateral surface, the bottom wall of each channel being 5 undercut at eac-h end, of a bulb, and terminal plates carried by said bulb, said plates being provided with a narrowed tongue lying in said channel, lips being provided at each cnd of'said tongue extending in said undercut ends.

4. In an incandescent electric combination with a base of insulating materialgsaid base having aconical socket in its front end and channels in its lateral surface,

1.5 the bottom wall of each channel being underlamp, the I l cut at its rear end, of a bulb and terminal plates carried by said bulb, said plates being'. provided with narrowed tongues lying in said channels, the rear end of said tongues having inwardly turned lips lying in said undercut ends of the base and said plates having inturned shoulders lying in said conical socket.

In witness whereof, I, hereunto subscribe my naine this 30th day of January A. D., 1907.

EDWARD B. CRAFT.

Witnesses y R. G. JonANsEN, ROY. T. ALLowAY. 

